Conventionally, in the pneumatic tire, for various purposes such as securement of a steering stability, a ride quality and a braking performance, there can be listed up a structure in which a tread rubber forming a ground surface is asymmetrically mixed so that a composition is different between a mounting inner side and a mounting outer side of the tire.
For example, in Patent Document 1, there is disclosed a matter that a steering stability is improved by arranging a high-hardness rubber in a mounting outer side area of a cap rubber (a tread rubber) forming a ground surface, and arranging a low-hardness rubber in a mounting inner side of the cap rubber.